Posted
by
timothy
on Tuesday July 14, 2009 @10:07AM
from the now-a-respectable-middle-class-planet dept.

Matt_dk writes with this excerpt from Space Fellowship: "Venus Express has charted the first map of Venus' southern hemisphere at infrared wavelengths. The new map hints that our neighbouring world may once have been more Earth-like, with a plate tectonics system and an ocean of water. The map comprises over a thousand individual images, recorded between May 2006 and December 2007. Because Venus is covered in clouds, normal cameras cannot see the surface, but Venus Express used a particular infrared wavelength that can see through them."

No, I blame the people who didn't want to burn greenhouse gases who pushed everyone to use renewable sources like "Geo-thermal" or "Venu-Thermal" energy that caused plate tectonics to grind to a halt and the outer crust to solidify and thicken which was all well and good until a few hundred million years later all of that internal Venusian heat had to go somewhere and lo and behold instant planet wide resurfacing and extreme out gassing.

The Eco-nuts of Venus were all proud of their renewable energy plan for geothermal until the fateful day the surface of the planet melted and they were all screwed. Thanks eco-nuts!!! Now there is one less habitable planet in the solar system! Too bad all of the amazon Venusian Women melted in the great planetary resurfacing 500 million years ago.

Plate tectonics stopped on venus long ago and this lead to overheating which caused a massive planet wide resurfacing and out gassing ever few hundred million years, causing venus to be the craphole it is now. If it had a moon and decent rotation plate techtonics would have likely been persevered. and life may still have been there.

Planetary rotation and the presence of moons has nothing to do with plate tectonics. The moon's gravity isn't strong enough to move whole sections of the planet's crust. The direction of plate motion varies from place to place and over time. If it were affected by the Earth's rotation, plates would only move CCW or CW. Plate motion on Earth is powered by mantle convection - magma from the lower mantle rising towards the surface, cooling, sinking back down, heating up, rising, etc. The recycling of magma essentially drags the plates around, like a conveyor belt.

Venus has a kind of tectonic cycle, but it works much differently. Based on the presence and relative age of craters and volcanoes on the surface, Venus seems to undergo catastrophic, global volcanism every 500Ma. This massive periodic volcanism, among other things, replenishes the planet's super-thick CO2 atmosphere. Otherwise, solar winds would have long ago stripped Venus of its atmosphere, since the planet has no significant magnetosphere.

Very nice description. However, Earth's plate tectonics can affect the rate of recession of the Moon. The configuration of the continents controls the size of the ocean basins, which in turn controls how dissipative the Earth is. The dissipation rate controls how quickly angular momentum is transferred from the Earth's rotation to the Moon's mean motion. As the moon gets more angular momentum, it moves away from the Earth.

That said, I agree with your post. I just thought this was a neat, if only tan

I've never heard that one before. I know that tidal forces are slowing down the Earth-Moon system's rotation and are causing the Moon to drift farther from the Earth. But, it makes sense that the distribution of ocean water would impart some variability to the equation. I wonder if the Tharsis Bulge on Mars has similar effects . ..

You know, I always tell my students (I'm an earth science professor at a community college in NYC) that Plate Tectonics explains everything on Earth. This is another great ex

Assuming life was able to start there in the first place (and given large amounts of water and the right temperature, it seems possible it could had).
Organisms that thrived on excess CO2 and helped trapped excess CO2 should have flourished and helped regulate the atmosphere.

Gaia Theory, as I learned it back in college, is simply a way of expressing the variety of organic/inorganic cycles that mediate conditions on a planet. The carbon cycle is an excellent example of this. Photosynthetic plankton absorb CO2 from the atmosphere, die, and eventually become seafloor sediment. That carbonate rock is eventually subducted into the lower mantle where it melts and fuels volcanic eruptions, rereleasing the CO2 into the atmosphere. Long-term changes in plankton populations can lead

You misread what I wrote. Based on the parent I responded to, my reply is based on the assumption that life was present before the runaway CO2 cycle.

Which, if assumed, would be an issue for Gaia theory since the self regulation of conditions favorable for life did obviously not occur. Obviously there are circumstances that one could assume that Gaia couldn't overcome. But on such long timescales, it would be a dent in the armor of Gaia.

For the same reason people who think for sure they'd be a part of Star Fleet if it existed very rarely join the military.

Most people who dream of flying a star ship will never go about taking up flying the planes that we DO have available to us.

Most people who cheer on the Rebels in Star Wars would never ever think of taking up arms against a hostile government.

All in all, a lot of people are dreamers rather than actual doers. As a person who still is a fan of Sci-fi - your sentiment is one that I realized myself a while back, and I've personally chosen to make an active attempt to enjoy and accept the time I live in, and the technology available to me. While fun in it's own way, if all you do is look wishfully towards a future that we'll never see (and likely won't quite materialize the way we envision it anyways), then life gets kind of boring after a while.

For the same reason people who think for sure they'd be a part of Star Fleet if it existed very rarely join the military.

In the Star Trek universe, Star Fleet is the only organization that does anything interesting. Colonists are basically cannon fodder. Corporations are corrupt. Any scientific research is either driven by Star Fleet or megalomaniac/corrupt scientists (or both). It doesn't leave much choice.

For the same reason people who think for sure they'd be a part of Star Fleet if it existed very rarely join the military. [...] All in all, a lot of people are dreamers rather than actual doers.

No, that's a bunch of shit. The fictional Enterprise is on a mission of peaceful exploration, trying to help people. That's not what the U.S. military does! Helping people only happens when it supports some concrete goal, take a look at history if you aren't in line with that one. I don't join the military because I don't want to support American imperialism. I would join something like Starfleet, for obvious reasons.

I think you're projecting.

Most people who cheer on the Rebels in Star Wars would never ever think of taking up arms against a hostile government.

Because we still waste too much money fighting each other over whose god has the biggest dick, and too little of those resources into getting ourselves off this planet and ensuring the survival of our ecology?

The day the human race grows up and learns that it's real enemy is the universe - entropy - will be the day that we climb out of the cradle and learn what it means to grow up.

its easier to subtract out of venus' atmosphere than put in mars' atmosphere what isn't there. i didn't say EASY, i said EASIER

some sort of genetically engineered bug that sequesters all of the CO2 and H2SO4, and permanently precipitates it out, preferably leaving O2 and H2O. something that could live on top of the clouds and in them. there's a lot of energy in that atmosphere, and you're closer to the sun... which is actually good: something to work with. rather than being far from the sun and feeble with resources, like mars

again, this is in no way easy, but if we ever reach the technological acumen and sustained effort needed to terraform one of our neighbors, i really think venus is a much better target than mars. more available energy to work with, almost identical gravity profile, and the need to subtract something out of the atmosphere, rather than to somehow create what isn't there, which is a lot easier to do, logically

mars has a long and sustained following and fan base, in science fiction as well as real science, but venus is the real future of mankind's first off-world colonization (besides the moon), if we ever get to that level of sophistication to even consider the possibility

don't depend on temperature differences. the only difference between hypothetical terraforming bug #1, functioning at high temp, versus hypothetical terraforming bug #2, functioning at low temp, is that bug #1 will work orders of magnitude faster than bug #2. regardless, we're not going to be terraforming with industrial sized reactors that do depend upon temp differences, but with nanotech, or more likely, genetically engineered critters

furthermore, suncreen with high SPF is the least of your concerns. wit

The problem with Venus is that it is closer to the sun. Even if you converted Venus into Earth 2.0 it would almost certainly be too hot to live on. This means that you would need some way to cool the planet significantly as well as shield it better from the increased UV radiation. Not impossible but I'm not so sure it is a better target than Mars. The advantage of Mars is that you can build structures on the surface as a step towards terraforming and build up the process gradually. This is close to impossib

where the temperature is regularly 115 degrees. they do it by just not going outdoors that much and having good ac. so you live indoors on venus, and you have genetically engineered crops that can withstand the high temps and scorching rays (as well as cosmic rays and other nasty high energy rays, since venus has no geomagnetism). you could have some nice architecture with large bay windows, just no skylights;-P

now compare that limitation with mars, with the very low atmospheric pressure, the much lower gr

so you live indoors on venus, and you have genetically engineered crops that can withstand the high temps and scorching rays (as well as cosmic rays and other nasty high energy rays, since venus has no geomagnetism).

I'm not sure if you're kidding, so if you were, just ignore this, but Venus' surface temperature hovers around 460 degrees Celsuis. I don't think genetic engineering is going to create crops that will withstand being scorched to a black smudge in seconds.

Lets compare scientifically. We cannot use the actual temperature of Venus since this is dominated by the greenhouse effect of the atmosphere so lets use radiation. The mean distance of Venus to the sun is 108M km vs. 146M km for Earth so Venus will receive 1.83 times the radiation from the sun (1/r^2). We can assume that it radiates the sun's energy at the same rate (i.e. assume equilibrium) so using Stefan's law we see that the radiation rate is proportional to T^4 (where T is in Kelvin).
Hence if Venus

Actually from many things I have seen, Mars would actually be easier to terraform, but I have always thought that Venus had more long term potential. A couple of years ago I saw a suggestion of a system to terraform Mars that is within our current technological capability. The article ran all of the numbers and it would work. The basic idea was that you find an ice asteroid or two and crash them into Mars. This would provide the missing water and help increase the density of the atmosphere (it has been long

unfortunately it also means that in the event of some freaky sun-related incident like a giant solar flare, electronic devices on venus will be fried way easier than anything on earth, or especially mars. (although maybe i'm wrong about the mars part. after all, it doesn't have a humongous magnetic field protecting it...)

but i always thought venus was a better target for terraforming.
its easier to subtract out of venus' atmosphere than put in mars' atmosphere what isn't there. i didn't say EASY, i said EASIER.
some sort of genetically engineered bug that sequesters all of the CO2 and H2SO4, and permanently precipitates it out, preferably leaving O2 and H2O. something that could live on top of the clouds and in them.

Actually, no, it's way harder to terraform Venus than it is to terraform Mars. The "just introduce algae" idea was proposed in 1961 by Carl Sagan, before the full extent of just how awful Venus' atmosphere was was fully appreciated. Venus has 90 atmospheres worth of carbon dioxide, and pretty much no available hydrogen. If you want to convert carbon into organic molecules, you need to have hydrogen - carbon alone is not sufficient. But if by some chance you did somehow convert 90 atmospheres worth of carbon dioxide into carbon and oxygen, what you'd wind up with is a furnace-hot planet with 60 atmospheres of pure oxygen and a layer of flammable carbon several hundred feet thick. This is not a stable situation, it'll go right back to the way it is now very quickly and spectacularly (though since the carbon would have been burning as fast as it's produced you'd never get such an extreme disequilibrium in real life). The permanent sequestration of all that carbon dioxide will require the addition of more material to the planet's atmosphere from the outside than would be required to give Mars a whole new atmosphere from scratch.

Furthermore, once you've given Venus an Earthlike atmosphere, there's another issue to consider; Venus has a rotation that's 243 Earth days long. Night lasts for 122 days on Venus. Without its ultra-dense atmosphere to convey heat around it's going to get extremely cold in the dark. We'll have to come up with a whole new ecology to endure those conditions and it doesn't sound all that fun for human inhabitants.

Or we'd have to do something at least as difficult as adding an atmosphere to Mars, slam asteroids into Venus in exactly the right way to speed up its rotation. FYI, a martian day is already quite close in length to an Earth day.

The whole completely replacing the crust every half billion years that theorized to happen on Venus is a bit of an inconvenience as well.

if you actually converted venus's atmosphere to something approximating earth's, it wouldn't be as hot anymore. right now, venus is the same temp, pole to equator, night to day. but reduced, the atmosphere would be like living in the desert, you'd have very cold nights, and very hot days. and since a day on venus is 100 days long, it means you'd have a siesta culture where everyone stays inside midday, and inside midnight. dawn and dusk would be pleasant in between, and dawn and dusk would last weeks. ecolo

as for your unstable balance of o2 and carbon, thats pretty much earth, right now. i can walk into most any nonwater environment on earth and start an inferno by myself if i wanted to. and yet our biosphere has lasted a plenty long time, mainly because the biosphere maintains the balance. it would be maintained biologically the same way on venus

I think you're underestimating the magnitude of the difference here, and just how reactive that much pure oxygen would be. The Apollo 1 fire happened because the

with mars, you're faced with the problem of making an atmosphere where there isn't any. that seems like a harder problem than getting a high oxygen atmosphere to behave. you talk about bombarding venus with alkali metals or calling up lando calrissian: these seems way harder to me

" Photosynthetic life might help maintain a livable environment after you've made it livable, but it's not going to get there by itself - no way no how"

with mars, you're faced with the problem of making an atmosphere where there isn't any

There is a vast amount of CO2 absorbed into the rock and soil on Mars. If you raised the temperature a little some of that would come out. As the absorbed CO2 was released the green house effect would increase and even more would be released. The cycle would continue until all the CO2 was released and an air pressure that you could survive without a space suit would be available.

We could always speed up the rotation of Venus by throwing a moon-sized object into orbit around it. Might actually solve the magnetic field issue by spinning the Venusian metal core potentially generating a magnetic shield around Venus just as Earth is shielded.

Something closer to our current tech would be to plant ion drives all over the surface and take sulfur from the atmosphere as the reaction mass and use them to spin up the planet while removing the excess sulfur and releasing oxygen. Naturally t

There seem to be a high percentage of historically "Wet" satellites in our solar system. Earth,Venus, Mars possibly Europa, Titan.......
Are our assumptions about solar system formation and the likely hood of liquid water covered satellites off?

Indeed, it seems our planet is situated in the middle of a graveyard. Could it be that the "wet phase", many / all rocky planets seem to go through (our current one on Earth has lasted about 4 billion years) is just temporary? Is the Earth an exception to this rule, in that it seems to have achieved stability, or will we eventually dry up as well?

I guess it's like emptying a bag full of coins on the floor from a height. The will bounce and flip and spin, but eventually they will all settle either on heads (

You got me, I wasn't trying to saying Venus didn't have an atmosphere, but its lighter gases (Hydrodren, Helium, Oxygen were all burned and or pull off) do to its close proximity to the sun. Leaving it with the dense gases which it is currently made of (Nitrogen and Carbon dioxide..maybe a little methane, but don't quote me I haven't taken an atronomy class since freshman year of college). So sorry in forgetting to say part of.

If this is true, Venus is now the number one planet to study. If it started out to be that much more Earthlike than we had previouly figured out to be than we need to know what happened to turn a potential Twin Earth to Hell. And is Earth going towards the same route and how much may Humanity have to say about it one way or the other? Why is it's rotation so slow? (Little known factiod, the extra weird thing about Venus' rotation is that it is locked to Earth in that whenever it is at closest approach to

Further down, if you would like to look, but I meant to say part of its atmosphere, which include the lighter elements of Oxygen, Helium, and Hydrogen. This left the denser elements which it consists of now(Nitrogen and Carbon dioxide.)

I have always thought that if Venus had formed in Mars orbit, we would likely have a true second Earth in our solar system. It would have been able to retain surface water. It would have a significant atmosphere. What its atmosphere would be like, I don't have the expertise to hypothesize, but it would have evolved far differently than the current Venusian atmosphere.

The highest temperature ever recorded on Mars is 70F / 21C. With an atmosphere and the greenhouse effect, a Venus in Mars orbit would be si

Umm... someone correct me, but doesn't Venus have a pretty THICK atmosphere, rather? Just with insane pressure and a composition that would even make smog-accustomed LA residents refuse to take a breath?

Venus is actually quite terra-formable. It does have an atmosphere, an extremely thick one at that, which has caused its high temperature. It also has gravity closer to ours than the moon or Mars. If we could turn the CO2 into O2 and usable carbon (like for soil), we could eventually live on it. Wouldn't be easy, but probably more feasible than terra-forming Mars.

Just because you are wrong and I called you out on it doesn't mean I am a Troll.

Gravity is a nice thing, but since you eventually want to launch more stuff into space, Mars-like gravity is better than something close to 1g. It allows all the niceties (indoor plumbing, showers, toilets, kitchens, cups of coffee, etc) while still making it much easier to launch something.

If we could turn the CO2 into O2 and usable carbon (like for soil), we could eventually live on it.

How about bio-engineering some extremophiles to due some conversions for us? Then, when we land, we just release some extremophile-eating microbes to clean up. Then winter comes, and they all freeze to death.

I was thinking that too, but can any organism in existence thrive at 422-442 celsius (792F - 828F), consume CO2 and expell O2 at a good speed (approx 25 years?) Can it be bio-engineered?
Oh, and we have to keep it dormant for the trip to Venus, have it survive impact, wake up after the trip, then we have to be able to handle it after the work is done.

I was wondering what would happen if you placed a mirror in an orbit between the sun and Venus so that the mirror remained between the two at all times (I am sure there is a term for it, geostationary but relative to the sun). Anyhow, if it were a few tens of square miles, would it be able to deflect enough of the sun's energy to bring about an appreciable drop in temperature. My thought is that once you started the cooling, that other processes like thinning of the atmosphere would cause a multiplier effec

IANAOMS, but I think that for the mirror to be stable at an orbit closer than Venus, it would have to move faster than Venus. If it moved at the same angular velocity as Venus, but was closer in, I think it would be unstable and eventually fall into the Sun. A series of shields in stable orbit around Venus, each a couple of thousand square km, might work better... Cooling the atmosphere is certainly a requirement, but I think that you would need to remove the CO2 before you saw additional benefit. You w

The day length (one sunrise to the next) on Venus is 116.75 Earth days. Interestingly it takes 243 Earth days to rotate a full 360. That's more than a Venusian year (224.7 days)!

Anyway, that long a day would be tough to adapt to. You'd essential have a year in 117 days with very hot summers and very cold winters. But I had a thought that you put a very large mirror in a 24 hour orbit around Venus so as it passes in front of the Sun it provides a simulated night on the sunlit side (I did say very large)

Plenty of hydrogen in the atmospheric sulfuric acid. Also, a Venusian day is 243 days back here on Earth; this is related to Venus being the only planet to rotate backwards compared to the other planets, probably the result of a collision long ago.

Nowhere near "plenty" as far as the job of converting all that CO2 into organic molecules is concerned, unfortunately. Have a look at http://en.wikipedia.org/wiki/File:AtmosphereofVenus.png [wikipedia.org] - the only hydrogen-bearing compound abundant enough to even make it on the chart is water vapor, at twenty parts per million.

There is the minor problem of the small fraction sulphuric acid and the small amount of nitrogen. If we really converted all the CO2 to O2 then fires would be a major concern. We would actually need to remove a large fraction of the atmosphere, add nitrogen (or other inert gas), filter out the H2SO4 and also find some way to massively increase the albedo to reduce the far greater heating from the sun.
If you can do all of that then you are right - Venus is terraformable. Short of them finding the cure for

There's no need to add nitrogen. Nitrogen is only 3.5% of Venus' atmosphere, but thanks to the sheer mass of Venus' atmosphere this is still more than three times as much nitrogen as is present in Earth's atmosphere.

Right, which is why the best thing to do with all the CO2 in the atmosphere is to make it into some sort of a solid carbonate. "Clean coal" dreamers claim that just injecting CO2 under the crust will make this happen on Earth - I suspect it's more complicated, but when we're already fantasizing about teraforming, the question of sequestering CO2 somehow is probably not the decisive one. Also, re. the earlier comment about the albedo: you could achieve the same effect cheaper by putting a huge solar-powered space station into the liberation point between Venus and the sun. Then you can spread out sails to block as much sun as you need until Venus gets just the perfect amount. This would be even better than Earth, because by manipulating the shade, you could control the illumination of various regions to ensure optimal weather year round.

Venus is actually quite terra-formable. It does have an atmosphere, an extremely thick one at that, which has caused its high temperature. It also has gravity closer to ours than the moon or Mars. If we could turn the CO2 into O2 and usable carbon (like for soil), we could eventually live on it. Wouldn't be easy, but probably more feasible than terra-forming Mars.

Hah! Venus is not even close to being as easy to terraform Mars.

Step 1. Cool down the planet. I suppose this could be done by placing a single huge or many smaller solar shades at the SOL-Venus L1.
Step 2. As the planet cools, the CO2 in the atmosphere will begin to freeze and fall to the surface. That dry ice needs to be sequestered into a more stable form, like calcium carbonite or maybe even diamond..
Step 3: Venus has a day that lasts 243 Earth days. The only way to speed up this rotation is to smac

Huh? Venus has a dense atmosphere - much denser than Earth's (something like being under 1km of water at the surface). I believe you meant lost its water, not atmosphere. While Venus is closer to the sun than Earth, it gets about one quarter the sunlight of Mercury yet has a higher maximum surface temperature to to the greenhouse gas effect.

So beyond just the heat, a human would need either liquid breathing or a rigid articulated pressure controlled suit, and liquid breathing has plenty of issues for an

I like to point out to those people that granite is radioactive and some forms have been shown to give off levels of radon several times higher than the FDA recommends as safe. Then ask how much food they prepare on them.